By the time he left the Renaissance city of Lucca on Tuesday, his standing on the world stage - and that of Britain - was unquestionably diminished and his own colleagues were suggesting his grand plan failed because it had been drawn up “on a whim”.

What made matters worse was that Mr Johnson had staked his credibility on gaining a consensus at the G7 meeting of foreign ministers.

Having cancelled a trip to Moscow last weekend to leave the way clear for the US Secretary of State Rex Tillerson, who arrived in the Russian capital last night, he had been mocked as America’s “poodle” by the Liberal Democrat leader Tim Farron.

His aides responded by saying that he had cancelled his trip to concentrate on winning the G7’s backing for his proposed carrot and stick approach to Mr Putin - threatening new sanctions while offering Russia the chance of rejoining the G7 if it pulled out of Syria.

Had it worked, he would have been hailed as a skilled statesman. Instead, his plan was vetoed in favour of an independent investigation into who carried out last week’s nerve gas attack. Russia’s embassy in London gleefully said he had “botched it”.

The Foreign Secretary’s hopes of securing unanimous backing from the G7 nations for fresh sanctions against Russia was doomed from the start, according to those close to the negotiations, because Germany and Italy have vested interests in maintaining good relations with Moscow.

Existing sanctions on Russia, imposed after its annexation of Crimea in 2014, have already cost the Italians £3.4bn in lost business, and Rome has resisted previous attempts to expand penalties on Moscow. Germany, meanwhile, imports 35 per cent of its oil from Russia.

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He's behind you: Rex Tillerson will arrive in Moscow with carrot, but no stick, after Boris Johnson's failed bid to move for new sanctions on RussiaCredit: REUTERS

A Government source said Mr Johnson had failed to do his homework, telling The Telegraph: “This was something that was sprung on a whim with no preparatory work. It was not particularly surprising that Germany voted it down because of the sensitivities over their energy supply from Russia.

"They would have cut off their own power. The lack of preparation has come back and bitten us.”

Rather than threatening Vladimir Putin with asset-freezing, the Germans preferred a policy of “reaching out to Russia” while Italy’s foreign minister said it was vital not to “push Russia into a corner”.

The suggestion that Mr Tillerson might offer something that will change the Kremlin’s mind on Assad is naïve

Fyodor Lukyanov, Council on Foreign and Defence Policy

The Italian foreign minister Angelino Alfano said: "There is no consensus at this time for new sanctions as an efficient method to reach our goal.

"There are obviously different opinions, and I am referring to my colleague Boris Johnson, who raised the issue. The position of the G7 is very clear. We support the sanctions that have already been introduced."

The German Foreign Minister Sigmar Gabriel said Russia and its ally Iran both had to be involved in the process of ending the conflict in Syria.

He said: "Not everyone may like it, but without Moscow and without Tehran there will be no solution for Syria.”

Mr Johnson’s aides insisted he had secured the agreement he wanted, because the ministers had agreed that sanctions against Russian and Syrian military officials could be threatened if an independent investigation by the Organisation for the Prohibition of Chemical Weapons proved Syria was to blame for the nerve gas attack.

But the French foreign minister Jean-Marc Ayrault told a rather different story.

"The question wasn't mentioned by anyone, except Boris Johnson, but we didn't talk about it any further," he said.

A 30-page statement from the G7 setting out what had been agreed at the meeting made no mention of sanctions in relation to Russia or Syria.

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Rex Tillerson arrives at Vnukovo International Airport in MoscowCredit: REUTERS

It meant that Rex Tillerson arrived in Russia on Tuesday night with a carrot, but no stick, and with no clarity over whether he would even be granted an audience with Mr Putin.

Fyodor Lukyanov, head of the Council on Foreign and Defence Policy, a think tank that advises the Russian foreign ministry, said Mr Tillerson and Mr Johnson had fundamentally misunderstood Mr Putin’s mindset.

He said: “The suggestion that Mr Tillerson might offer something that will change the Kremlin’s mind on Assad is naïve, and if someone seriously believes in that, it means people still don’t understand at all how Putin works.

"Abandoning Assad would be a profound change and a massive blow to the credibility of Russia in the eyes of the Western and non-Western countries.

"Putin never acts under pressure. If he does something he will choose a moment when it does not look like he is giving up.”

“Events have moved quickly,” said a Downing Street source, “but the fact that we are now in a position where the G7 and Middle Eastern countries say Assad must go will give Russia food for thought. We are in a stronger position now than we were at the weekend.”